卵白蛋白是蛋清中的主要蛋白质，利用卵白蛋白制备ACE抑制肽可为其高值利用提供参考。本文采用离子交换色谱对卵白蛋白的粗酶解物进行脱盐处理，确定了室温25 ℃、20 mL进样量、8 BV/h的脱盐工艺条件。在上述条件下，酶解物脱盐率达到83.6%，氮回收率和ACE（血管紧张素转换酶）抑制率分别为87.71%和80.31%。再采用截留分子量为10 ku和3 ku的两种超滤膜将脱盐酶解物分离成>10 ku、3~10 ku和<3 ku三个组分，最佳操作条件：超滤时间40 min、操作压力1.5 bar、温度35 ℃（10 ku）和30 ℃（3 ku）。超滤所得三个组分均具有ACE抑制活性，其中分子量<3 ku的超滤物活性最高，该组分与粗酶解物相比较，总巯基和表面巯基含量显著降低（p<0.05），同时表面疏水性显著提高（p<0.05），热稳定性增加。因此，卵白蛋白的粗酶解物经脱盐、超滤处理，可以明显去除其中的盐分，并得到ACE抑制活性较高的分离组分。

The preparation of angiotensin converting enzyme (ACE) inhibitory peptides from ovalbumin, the main protein in egg whites, can provide a reference for their value-added application. The desalination of crude enzymatic hydrolysates from ovalbumin in this paper was performed by ion exchange chromatography, using the following desalting conditions: room temperature (25 ℃), sample load of 20 mL, and flow rate of 8 BV/h. Under these conditions, the desalination rate of hydrolysates, nitrogen recovery rate, and ACE inhibition rate were 83.6%, 87.71%, and 80.31%, respectively. Two ultrafiltration membranes with molecular weight cut-offs of 10 ku and 3 ku were employed to separate the desalinated hydrolysates into three fractions: >10 ku, 3~10 ku, and <3 ku. The optimal operating conditions were as follows: ultrafiltration time of 40 min, operating pressure of 1.5 bar, and temperature of 35 ℃ for 10 ku or 30 ℃ for 3 ku. All three fractions showed ACE inhibitory activity, and the highest activity was found in the <3 ku fraction. Compared to crude hydrolysates, the total and surface hydrosulfuryl contents of the <3 ku fraction were significantly decreased (p < 0.05), the surface hydrophobicity was increased (p < 0.05), and thermal stability was improved. Therefore, desalination and ultrafiltration treatments can effectively reduce the salt content of crude enzymatic hydrolysates of ovalbumin and produce a fraction with high ACE inhibitory activity.

国家十二五支撑计划项目（2012BAD33B03）；国家自然科学基金项目（31470094）